Roll stand, with means for the fine adjustment of the rolls under rolling pressure

ABSTRACT

A roll stand, particularly for rolling sheets or strips, comprising coarse adjusting means for adjusting the rolls when unloaded, and hydraulic fine adjusting means for adjusting the rolls under rolling pressure, the fine adjusting means comprising an adjusting cylinder which bears upon a lower crosshead, and in which an adjusting plunger can be raised and lowered hydraulically, the free upper end of this adjusting plunger bearing against the under surfaces of the lower chocks, which are vertically movable in windows in the roll housing, the said adjusting cylinder forming the shifting plunger of a further hydraulic unit, between which and the lower crosshead is arranged a shifting cylinder accommodating the said shifting plunger, which bears with its free upper end against shoulders on the roll housing extending into the windows thereof.

United States Patent [72] Inventors Horst Willeke Dusseldorf; Wilhelm Beckmann, Ratingen, both of, Germany [2l I Appl. No. 759,047 [22] Filed Sept. ".1968 [45] Patented Aug. 3, I97] [73] Assignee Schloemtmn Akliengesellschaft Dusseldorl, Germany [32] Priority Sept. 13, I967 [33] Germany [31] p16 02176.4

[54] ROLL STAND, WITH MEANS FOR THE FINE ADJUSTMENT OF THE ROLLS UNDER ROLLING PRESSURE 9 Claims, 4 Drawing Figs.

[52] U.S.Cl. 72/240, 72/244, 72/245 [5]] Int. Cl B2lb3I/20, B2 1 b 31/32 [50] Field of Search 72/240,

[56] References Cited! UNITED STATES PATENTS 3,197,986 8/1965 Freedman et al. 72/16 Primary Examinen-Charles W. Lanham Assistant Examiner-E. M. Combs Al!orneyH0lman & Stern ABSTRACT: A roll stand, particularly for rolling sheets or strips, comprising coarse adjusting means for adjusting the rolls when unloaded, and hydraulic fine adjusting means for adjusting the rolls under rolling pressure, the fine adjusting means comprising an adjusting cylinder which bears upon a lower erosshead, and in which an adjusting plunger can be raised and lowered hydraulically, the free upper end ofthis adjusting plunger bearing against the under surfaces of the lower checks, which are vertically movable in windows in the roll housing, the said adjusting cylinder forming the shifting plunger of a further hydraulic unit, between which and the lower crosshead is arranged a shifting cylinder accommodating the said shifting plunger, which bears with its free upper end against shoulders on the roll housing extending into the windows thereof.

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ROLL STAND, WITH MEANS FOR THE FINE ADJUSTMENT OF THE ROLLS UNDER ROLLING PRESSURE This invention relates to hydraulic means for adjusting the rolls in roll housings under pressure.

It is known in principle to employ hydraulic power for adjusting the rolls of a rolling mill under pressure, the driving means consisting of a cylinder bearing in the crosshead of a roll stand and a piston guided in the cylinder, wherein the free end of the piston comes into contact with the chocks of the roll, as in German Pat. No. 631,564. This hydraulic adjusting of the rolls under loading by the rolling pressure has the advantage, as compared with mechanical adjusting by means of screw-threaded spindles, of being quicker in reaction, so that a quicker response is ensured, in regulating engagements, owing to deviations in the thickness of the stock.

It has also already been proposed, in a solution not yet pertaining to the state of the art, particularly in the case of roll stands for heavy plate, with a coarse adjusting means from above for the chocks of the lower backing roll, to fit into the roll stand a mechanical fine adjustment under roll pressure, in which a worm wheel movable from an adjusting drive is mounted upon a screw-threaded spindle provided with longitudinal grooves.

The head end of this threaded spindle bears against the lower bearing surface of the chock of the lower backing roll, The threaded spindle can be hydraulically raised and lowered relatively to a pressure nut within the limits of the threaded spindle, so that the mechanical fine adjusting means can be rotated under rolling pressure without an especially powerful drive,.as in our German Pat. application No. Sch 34,179 lb/7a. This solution is likewise impaired by the disadvantages of all mechanical adjusting means, namely comparatively great delay in response in operation.

The object of the present invention is to obtain, while utilizing the advantages of the hydraulic adjusting of the rolls under rolling pressure, a prompt response in the coarse shifting of the lower rolls, without having to put up with the disadvantages arising from the compressibility of the pressure fluid at relatively large stroke lengths, and furthermore without having to increase the intrinsic rigidity of the roll stand.

According to the invention, therefore, the adjusting cylinder of the hydraulic find adjusting means forms the shifting plunger ofa further hydraulic shifting means for the lower rolls, while between the latter and the lower crosshead is arranged a shifting cylinder accommodating the shifting plunger, and the shifting plunger can be clamped with its free end against shoulders or ledges. extending into the ,window space of the roll-stand.

In consequence of such a construction of the lower rollshifting means it is possible to adjust the lower working roll quickly to the rolling line, after a reduction in diameter occasioned by regrinding the roll and the lengthening of stroke arising therefrom, in order to straighten the lower roll, or, in four-high roll stands, the lower backing and working rolls, wherein, by the clamping of the shifting plunger in relation to the ledges in. the windows, a preclamping or prestressing of the housing parts located in the flow of power, and of the lower crosshead, is obtained at the same time, and with it the springing, particularly of the lower crosshead, under load, is substantially obviated. The stiffening obtained by the preclamping of the lower crosshead is here veryimportant, since the springing thereof constitutes a substantial part of the housing expansion.

According to a further feature, the shifting plunger is so constructed. as to be rotationally movable about its longitudinal axis, and is provided endwise with a stepped ring, the step segmentsof which, set in pairs at 180 to one another, will present a uniform height of step It. It is thereby rendered possible, according to the required stroke length of the shifting plunger, for the purpose of compensating for the grinding away of the rolls, to adjust a corresponding pair of stepped segments, in order in this way to vary the limitation of stroke of the end face of the shifting plunger in relation to theshoulders extending into the windows. The stepped ring is connected integrally with the shifting plunger. The stepped ring may even be mounted rotationally upon the shifting plunger. According to the construction the stepped ring and/or the shifting plunger are rotatable electromechanically, that is, with shifting motor and shifting gear, or by supplying pressure fluid to a lifting piston and toothed-rack gear, or a ratchet drive. The supply of pressure medium to the cylinder spaces of the adjusting or shifting cylinder is effected through ducts in the lower crosshead and in the shifting cylinder on the other hand. The rotary drive of the shifting plunger consists preferably ofa piston-rod gear with a toothed rack, and a ring of teeth arranged on the periphery of the shifting plunger or of the stepped ring.

One embodiment of the invention is illustrated by way ofexample in the accompanying drawings, in which:

FIG. I shows a four-high roll stand with hydraulic roll-adjusting means;

FIG. 2 shows the hydraulic roll-adjusting means in cutout, partly in section, and on a larger scale;

FIG. 3 is a plain view of the shifting device; and

FIG. 4 shows spacers or shims substituted for the stepped ring.

By 1 is denoted a roll housing, in this case that ofa four-high roll stand, which comprises an upper backing roll 3 and a lower backing roll 5. The backing rolls 3 and 5 are so supported in chocks 6 and 7, and the working rolls 2 and 4 in chocks 8 and 9, as to be movable in a vertical plane. 1n the roll housing 1 are arranged housing rollers 10, extending, with their delivery rollers 11, to form a delivery line in the rolling line W.

The upper backing roll 3 is adjustable in a known manner by coarse adjusting means consisting of screw-threaded spindles 12, to a roll gap associated with a definite reduction per pass, in that by rotating the threaded spindles 12, by means of a drive not further illustrated, the chocks 6 of the upper backing roll 3 are lowered or raised into a definite position for the balancing ofthe rolls.

The line adjusting of the upper edge of the lower working roll to the rolling line W, taking with it the lower backing roll 5, is effected by supplying fluid to an adjusting cylinder 14, which is guided in a shifting cylinder 16, and which is known as a shifting plunger, pressure medium being guided into a cylinder space 16a by way ofa pressure-medium inlet 16b.

The upper end face of the adjusting cylinder 14 is constructed as a stepped ring 18, which is formed of stepped segments 119 set in pairs of segments of equal height h, at from one another.

As illustrated in FIG. 2, the stepped ring 18 is connected integrally with the adjusting cylinder 14. Alternatively, however, the stepped ring may be arranged rotatably upon the adjusting cylinder 14, as indicated in FIG. 3.

The individual pairs of segmental steps 19 are of different heights h,, h h and so forth, in order to compensate for different reductions in diameter of the rolls upon the dressing thereof.

In the adjusting cylinders M are arranged adjusting plungers 15, which bear, through pressure plates 15b, against the lower chocks 7 of the lower backing roll. 5. By supplying pressure medium to a cylinder space 14a through a pressure-medium inlet 15a, the position of the upper edge of the lower working roll 4 can be altered under rolling pressure, so that it is possible to influence the rolled stock during the rolling process even in operative condition, under rolling pressure.

In order, however, even after a maximum roll-grinding reduction, involving a reduction in diameter of the lower working roll 4 and also of the backing roll 5, to be able to adjust the edge of the lower working roll 4 to the rolling line W with a relatively large stroke, the adjusting cylinder 14 is provided on its end. face with the stepped ring 18.

By supplying fluid to the cylinder space 16a of the shifting cylinder 16 the adjusting cylinder 14 is caused to bear with its end faces against steps or shoulders 17 on the roll housing 1, and to preclamp the lower portion of the housing, including the lower crosshead 1a, with a preclamping force which is greater than the rolling pressure.

The shifting of the adjusting cylinder 14 with an integral connection with the stepped ring 18, or of the stepped ring 18 alone insofar as the stepped ring 18 is rotatably mounted upon the actual adjusting cylinder 14, is effected by the end face of a piston rod 22 entering recesses 21 on the periphery of the stepped ring 18, and, by a cylinder 23 being energized with pressure medium, thereby rotating the ring 18. The cylinder 23 is rockable in a horizontal plane about an axis of rotation 25, and is urged by the pressure of spring 26 into the recesses 21.

Instead of the stepped ring 18, shims or spacers 18b may be employed, as illustrated in FIG. 4.

The invention is likewise applicable to two-high roll stands. The shifting drive of the stepped ring 18 may also be effected by means of a toothed-rack gear, a ratchet drive, or an electrical shifting drive.

The method of operation of this roll-adjusting means is as follows: In the constructional example of the four-high roll stand 1 illustrated, the upper working roll 2 and also the upper backing roll 3 are adjusted, by means of the threaded spindle 12, to the roll gap required for the reduction per pass that is provided. By means of the lower shifting device, by supplying fluid to thecylinder space 16a of the shifting cylinder 16, the shifting plunger 14, which also forms the adjusting cylinder, is so far raised that its end faces, with the interposition of the largest pair of stepped segments 19, bear against the shoulders or steps 17 projecting into the housing windows of the roll housing 1, and, by way of the shoulders 17 and the lower housing crossbars, as well as the lower crosshead 1a, preclamp these members, with a force which is greater than the rolling pressure, whereby a springing ofthese members is precluded.

Hence, the shifting device produces the result that the lower working roll 4, together with the lower backing roll 5, is raised so far that the upper edge of the lower working roll 4 is adjusted to the desired rolling line W.

The shifting of the lower working roll 4 and of the lower backing roll 5 for the regulating of differences in thickness in the rolled stock is effected under rolling pressure during the rolling operation by supplying fluid to the cylinder space 14a, whereby the adjusting plungers 15, bearing with their upper end faces against the lower bearing surfaces of the chocks 7, raise the lower working roll'4, together with the lower backing roll 5. lf, after a change of working rolls and the insertion of reground working rolls 2, 4 and/or backing rolls 3, 5, the upper edge of the lower working roll 4 is no longer on a level with the existing rolling-line adjustment, a similar pair of stepped segments 19, corresponding to the reduction in diameter of the rolls, is moved in between the shoulders 17 and the end faces of the shifting plungers forming the adjusting cylinders 14. Owing to the smaller height of this pair of stepped segments 19, the end face of the adjusting plunger 15, and with it also the upper edge of the lower working roll 4, can be lifted up into the position which they had occupied before the regrinding of the rolls, since the stroke of the adjusting cylinder 14, by employing a shim or spacer 18b of less height, or in consequence of the use of a pair of step'ped segments 19 of smaller height, is increased. ln'this way the position of the lower working roll 4, lowered by the regrinding of the roll, is raised again. 1' 1 The fine adjustment of the lower working roll 4 and of the lower backing roll 5, for the regulating of differences of thickness in the roll stock, is effected, as already described, during the rolling operation, under rolling pressure.

We claim:

1. A roll stand comprising: lower crossheads, roll housings formed with windows, upper and lower chocks, carrying the rolls, and movable vertically in the said windows, coarse adustlng means for ad usting the rolls in an unloaded condition,

hydraulic fine adjusting means for adjusting the rolls under rolling pressure by adjusting the chocks, the said fine adjusting means comprising in each roll housing: shoulders extending into the said windows, an adjusting cylinder, also acting as a shifting plunger, bearing upon the lower crosshead, an adjusting plunger capable of being raised and lowered by fluid pressure in the said adjusting cylinder, the free upper end of the said adjusting plunger bearing against the underside of the lower chock, characterized by the feature that the roll housing also comprises: a hydraulic shifting cylinder for straightening the lower rolls to the rolling line, the adjustment cylinder being movably supported in this hydraulic shifting cylinder, and means for preclamping the upper edge of the adjusting cylinder relatively to the shifting cylinder, which is located between the lower crosshead and the shoulders of the roll housing.

2. A roll stand as claimed in claim 1, the shifting plunger being rotatable about its longitudinal axis, and further comprising endwise a stepped ring consisting of pairs of segmental steps, each pair consisting of two steps of the same height spaced apart by but the height of the steps of each pair being different from that of other pairs.

3. A roll stand as claimed in claim 2, the stepped ring being integral with the shifting plunger.

4. A roll stand as claimed in claim 2, the stepped ring being rotatably mounted upon the shifting plunger.

5. A roll stand as claimed in claim 2, further comprising electromechanical means for rotating the stepped ring.

6. A roll stand as claimed in claim 2, further comprising hydraulic means for rotating the stepped ring.

7. A roll stand as claimed in claim 1, the adjusting plunger being formed with ducts for the admission of liquid to the cylinder space of the adjusting cylinder; and the shifting cylinder and the housing being formed with ducts for the admission of pressure liquid to the cylinder space of the shifting cylinder.

8. A roll stand as claimed in claim 6, further comprising ratchet teeth on the stepped ring, and a piston and cylinder unit, the piston rod of which bears against the said ratchet teeth.

9. A roll stand as claimed in claim 1, further comprising spacing members of different thicknesses adapted to be interposed between the shifting plunger and the shoulders against which it bears. 

1. A roll stand comprising: lower crossheads, roll housings formed with windows, upper and lower chocks, carrying the rolls, and movable vertically in the said windows, coarse adjusting means for adjusting the rolls in an unloaded condition, hydraulic fine adjusting means for adjusting the rolls under rolling pressure by adjusting the chocks, the said fine adjusting means comprising in each roll housing: shoulders extending into the said windows, an adjusting cylinder, also acting as a shifting plunger, bearing upon the lower crosshead, an adjusting plunger capable of being raised and lowered by fluid pressure in the said adjusting cylinder, the free upper end of the said adjusting plunger bearing against the underside of the lower chock, characterized by the feature that the roll housing also comprises: a hydraulic shifting cylinder for straightening the lower rolls to the rolling line, the adjustment cylinder being movably supported in this hydraulic shifting cylinder, and means for preclamping the upper edge of the adjusting cylinder relatively to the shifting cylinder, which is located between the lower crosshead and the shoulders of the roll housing.
 2. A roll stand as claimed in claim 1, the shifting plunger being rotatable about its longitudinal axis, and further comprising endwise a stepped ring consisting of pairs of segmental steps, each pair consisting of two steps of the same height spaced apart by 180*, but the height of the steps of each pair being different from that of other pairs.
 3. A roll stand as claimed in claim 2, the stepped ring being integral with the shifting plunger.
 4. A roll stand as claimed in claim 2, the stepped ring being rotatably mounted upon the shifting plunger.
 5. A roll stand as claimed in claim 2, further comprising electromechanical means for rotating the stepped ring.
 6. A roll stand as claimed in claim 2, further comprising hydraulic means for rotating the stepped ring.
 7. A roll stand as claimed in claim 1, the adjusting plunger being formed with ducts for the admission of liquid to the cylinder space of the adjusting cylinder; and the shifting cylinder and the housing being formed with ducts for the admission of pressure liquid to the cylinder space of the shifting cylinder.
 8. A roll stand as claimed in claim 6, further cOmprising ratchet teeth on the stepped ring, and a piston and cylinder unit, the piston rod of which bears against the said ratchet teeth.
 9. A roll stand as claimed in claim 1, further comprising spacing members of different thicknesses adapted to be interposed between the shifting plunger and the shoulders against which it bears. 